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  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Load .GLTF - Car Path</title>
    <style>
    html, body {
        margin: 0;
        height: 100%;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
  </body>
<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js",
    "three/addons/": "../../examples/jsm/"
  }
}
</script>

<script type="module">
import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

function main() {

	const canvas = document.querySelector( '#c' );
	const renderer = new THREE.WebGLRenderer( { antialias: true, canvas } );

	const fov = 45;
	const aspect = 2; // the canvas default
	const near = 0.1;
	const far = 100;
	const camera = new THREE.PerspectiveCamera( fov, aspect, near, far );
	camera.position.set( 0, 10, 20 );

	const controls = new OrbitControls( camera, canvas );
	controls.target.set( 0, 5, 0 );
	controls.update();

	const scene = new THREE.Scene();
	scene.background = new THREE.Color( 'black' );

	{

		const planeSize = 40;

		const loader = new THREE.TextureLoader();
		const texture = loader.load( 'resources/images/checker.png' );
		texture.wrapS = THREE.RepeatWrapping;
		texture.wrapT = THREE.RepeatWrapping;
		texture.magFilter = THREE.NearestFilter;
		texture.colorSpace = THREE.SRGBColorSpace;
		const repeats = planeSize / 2;
		texture.repeat.set( repeats, repeats );

		const planeGeo = new THREE.PlaneGeometry( planeSize, planeSize );
		const planeMat = new THREE.MeshPhongMaterial( {
			map: texture,
			side: THREE.DoubleSide,
		} );
		const mesh = new THREE.Mesh( planeGeo, planeMat );
		mesh.rotation.x = Math.PI * - .5;
		scene.add( mesh );

	}

	{

		const skyColor = 0xB1E1FF; // light blue
		const groundColor = 0xB97A20; // brownish orange
		const intensity = 2;
		const light = new THREE.HemisphereLight( skyColor, groundColor, intensity );
		scene.add( light );

	}

	{

		const color = 0xFFFFFF;
		const intensity = 2.5;
		const light = new THREE.DirectionalLight( color, intensity );
		light.position.set( 5, 10, 2 );
		scene.add( light );
		scene.add( light.target );

	}

	function frameArea( sizeToFitOnScreen, boxSize, boxCenter, camera ) {

		const halfSizeToFitOnScreen = sizeToFitOnScreen * 0.5;
		const halfFovY = THREE.MathUtils.degToRad( camera.fov * .5 );
		const distance = halfSizeToFitOnScreen / Math.tan( halfFovY );
		// compute a unit vector that points in the direction the camera is now
		// in the xz plane from the center of the box
		const direction = ( new THREE.Vector3() )
			.subVectors( camera.position, boxCenter )
			.multiply( new THREE.Vector3( 1, 0, 1 ) )
			.normalize();

		// move the camera to a position distance units way from the center
		// in whatever direction the camera was from the center already
		camera.position.copy( direction.multiplyScalar( distance ).add( boxCenter ) );

		// pick some near and far values for the frustum that
		// will contain the box.
		camera.near = boxSize / 100;
		camera.far = boxSize * 100;

		camera.updateProjectionMatrix();

		// point the camera to look at the center of the box
		camera.lookAt( boxCenter.x, boxCenter.y, boxCenter.z );

	}

	let curve;
	let curveObject;
	{

		const controlPoints = [
			[ 1.118281, 5.115846, - 3.681386 ],
			[ 3.948875, 5.115846, - 3.641834 ],
			[ 3.960072, 5.115846, - 0.240352 ],
			[ 3.985447, 5.115846, 4.585005 ],
			[ - 3.793631, 5.115846, 4.585006 ],
			[ - 3.826839, 5.115846, - 14.736200 ],
			[ - 14.542292, 5.115846, - 14.765865 ],
			[ - 14.520929, 5.115846, - 3.627002 ],
			[ - 5.452815, 5.115846, - 3.634418 ],
			[ - 5.467251, 5.115846, 4.549161 ],
			[ - 13.266233, 5.115846, 4.567083 ],
			[ - 13.250067, 5.115846, - 13.499271 ],
			[ 4.081842, 5.115846, - 13.435463 ],
			[ 4.125436, 5.115846, - 5.334928 ],
			[ - 14.521364, 5.115846, - 5.239871 ],
			[ - 14.510466, 5.115846, 5.486727 ],
			[ 5.745666, 5.115846, 5.510492 ],
			[ 5.787942, 5.115846, - 14.728308 ],
			[ - 5.423720, 5.115846, - 14.761919 ],
			[ - 5.373599, 5.115846, - 3.704133 ],
			[ 1.004861, 5.115846, - 3.641834 ],
		];
		const p0 = new THREE.Vector3();
		const p1 = new THREE.Vector3();
		curve = new THREE.CatmullRomCurve3(
			controlPoints.map( ( p, ndx ) => {

				p0.set( ...p );
				p1.set( ...controlPoints[ ( ndx + 1 ) % controlPoints.length ] );
				return [
					( new THREE.Vector3() ).copy( p0 ),
					( new THREE.Vector3() ).lerpVectors( p0, p1, 0.1 ),
					( new THREE.Vector3() ).lerpVectors( p0, p1, 0.9 ),
				];

			} ).flat(),
			true,
		);
		{

			const points = curve.getPoints( 250 );
			const geometry = new THREE.BufferGeometry().setFromPoints( points );
			const material = new THREE.LineBasicMaterial( { color: 0xff0000 } );
			curveObject = new THREE.Line( geometry, material );
			material.depthTest = false;
			curveObject.renderOrder = 1;
			scene.add( curveObject );

		}

	}

	const cars = [];
	{

		const gltfLoader = new GLTFLoader();
		gltfLoader.load( 'resources/models/cartoon_lowpoly_small_city_free_pack/scene.gltf', ( gltf ) => {

			const root = gltf.scene;
			scene.add( root );

			const loadedCars = root.getObjectByName( 'Cars' );
			const fixes = [
				{ prefix: 'Car_08', rot: [ Math.PI * .5, 0, Math.PI * .5 ], },
				{ prefix: 'CAR_03', rot: [ 0, Math.PI, 0 ], },
				{ prefix: 'Car_04', rot: [ 0, Math.PI, 0 ], },
			];

			root.updateMatrixWorld();
			for ( const car of loadedCars.children.slice() ) {

				const fix = fixes.find( fix => car.name.startsWith( fix.prefix ) );
				const obj = new THREE.Object3D();
				car.getWorldPosition( obj.position );
				car.position.set( 0, 0, 0 );
				car.rotation.set( ...fix.rot );
				obj.add( car );
				scene.add( obj );
				cars.push( obj );

			}

			// compute the box that contains all the stuff
			// from root and below
			const box = new THREE.Box3().setFromObject( root );

			const boxSize = box.getSize( new THREE.Vector3() ).length();
			const boxCenter = box.getCenter( new THREE.Vector3() );

			// set the camera to frame the box
			frameArea( boxSize * 0.5, boxSize, boxCenter, camera );

			// update the Trackball controls to handle the new size
			controls.maxDistance = boxSize * 10;
			controls.target.copy( boxCenter );
			controls.update();

		} );

	}

	function resizeRendererToDisplaySize( renderer ) {

		const canvas = renderer.domElement;
		const width = canvas.clientWidth;
		const height = canvas.clientHeight;
		const needResize = canvas.width !== width || canvas.height !== height;
		if ( needResize ) {

			renderer.setSize( width, height, false );

		}

		return needResize;

	}

	function render( time ) {

		time *= 0.001; // convert to seconds

		if ( resizeRendererToDisplaySize( renderer ) ) {

			const canvas = renderer.domElement;
			camera.aspect = canvas.clientWidth / canvas.clientHeight;
			camera.updateProjectionMatrix();

		}

		for ( const car of cars ) {

			car.rotation.y = time;

		}

		renderer.render( scene, camera );

		requestAnimationFrame( render );

	}

	requestAnimationFrame( render );

}

main();
</script>
</html>
